His future is very bright at Barcelona because when Xavi Hernandez was coach Lamine Yamal played quite often so he will get good experience, if Hansi Flick can continue to develop this player well because we often see how players who don't match the characteristics of the new coach at the club become stuck his appearance then he should be a Barcelona star and that is a club asset, and Barcelona will keep this player maybe he will only play at Barcelona, hopefully, he doesn't waste his career because many good players only last a short time and are forgotten because they don't develop well.
Yes the price is quite high even though we know yes, he’s got the quality and can be a good replacement for Mbappe. Also for Cancelo, he's a good player and he's performed very well for his teams. He was a good impact to City before he left on loan to Barcelona. Well, it's a good thing that Barcelona enjoyed him for the time being and if I'm to suggest, it'll only be right that they retain him in the team as he's going to be advantageous to them. Barcelona technically actually needs him there more than him at City. They're in financial debts no doubt but they have to make do with every situation they've found themselves.
Man City don't really have a need for him now as they've got the rightful replacement for him. The Spanish side just should strive to make him join the team even with the littlest funds available. Sale of Yamal can be an effect to them generating the finance too but it'll mean loosing a good player too. These two players are good and would definitely blend each other but the management just have to be careful in their decisions as it'll definitely affect the start up phase for the next season encounters.